[kosciusko51]

They will try to make ridiculous moral equivalencies, i.e. abortion vs. death-penalty, Israel's treatment of "palestinians" vs. Germany's treatment of Jews, etc.

They will refuse to accept the wrong-doings of their politicians or try to avoid it by bringing up some example of a Republican doing the same thing.

[Zeneta]

I find that asking them a lot of questions works very well when debating.

You can set up your questions in a way that they will box themselves into a corner. I would also note that usually when they recognize this, they will lash out with the most vile and hateful speech they can muster.